Automatic photographic gradation-measuring system for controlling auxiliary exposure means

ABSTRACT

The focal plane on which the photographic negative image is focused is divided into a number of parts respectively connected to light-transmitting members. The ends of the light-transmitting members are arranged in a circle and scanned by another lighttransmitting member which is connected to a light receptor. The output photocurrent from the light receptor is a measure of the photographic gradation of the negative image.

United States Patent [151 3,639,058 Kimura 1 Feb. 1, 1972 [54] AUTOMATICPHOTOGRAPHIC [56] References Cited GRADATION-MEASURING SYSTEM UNITEDSTATES PATENTS FOR CONTROLLING AUXILIARY 3 25 594 6/l96 G db 5 I XP REMEANS ,3 7 o ammer et al. ..3 0 96 X E OSU 3,298,296 H1967 Mey....355/70 X [72] Inventor: Tsutomu Kimura, Kanagawa, Japan 3,480,36311/1969 Stewart ..355/68 [73] Assignee: Fuji Photo Film Co., Ltd.,Ashigara- Primary Examiner samuel Matthews Kanagawa' Japan AssistantExaminer-Fred L. Braun 22 i Jam 9, 1970 Attorney-Sughrue, Rothwell,Mion, Zinn 8L Macpeak [21] Appl. No.: 1,669 [57] ABSTRACT I The focalplane on which the photographic negative image is [30] ForeignApplication Priority Data focused is divided into a number of partsrespectively connected to light-transmitting members. The ends of thelight- Jan. 25, 1969 Japan ..44/5581 transmitting members are arrangedin a circle and scanned by another light-transmitting member which isconnected to a [52] US. Cl ..355/83, 355/68 light receptor The outputphotocunem from the light recap [51 Ill. CI. tor is a measure of the p gp gradation of the negative [58] Field ofSearch ..355/35, 68, 70,71,80,83; image" 1 Claims, 4 Drawing Figures 3 F7 6 4 CONT DEVICE DE TE CTI N G DET ECT ION PORTION SHUTTER 8 CONTROLLER h AMPL I I I5 I4PATENTED FEB 1 I97? SHEET 2 OF 2 FIG.

FIG.

TIME

AUTOMATIC PI-IOTOGRAPI-IIC GRAD'ATION- MEASURING SYSTEM FOR CONTROLLINGAUXILIARY EXPOSURE MEANS CROSS-REFERENCE TO RELATED APPLICATION Thisinvention relates to my copending application Ser. No. 854,467, filedSept. 2, l969.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to a system for automatically measuring photographic gradation,and in particularly to a system for automatically measuring thephotographic gradation of a negative image in order to control auxiliaryexposure means for exposing photographic paper so that a positive imageof the optimum gradation may be made from various gradation negativeimages.

2. Description of the Prior Art Heretofore, in the case of making apositive image of optimum gradation from various degrees of gradation innegative images, the gradation of the negative image has been measuredor examined with the eyes of the operator, and according to theexperienced measurement, the operator himself selects a proper kind ofpaper for printing or the operator controls' the auxiliary exposure forcontrolling the gradation on the paper to obtain a positive image of theoptimum degree of gradation.

SUMMARY OF THE INVENTION In accordance with the present invention, anautomatic photographic gradation-measuring system is provided whereinthe optical density at various points or parts on the negative image isconverted into an output current by means of lighttransmitting means andlight receptors and the photographic gradation is automatically measuredrather than examining the gradation by the operators eyes.

The principal object of the present invention is to provide a system forautomatically measuring the photographic gradation of negative images.

Another object of the present invention 'is to provide a system forautomatically measuring the photographic gradation and to represent thegradation by an electrical output which can be utilized as the input toanother controlling system.

Other objects and fuller understanding of this invention will be madeapparent from the following description in detail taken in conjunctionwith the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view ofthephotographicprinting apparatus equipped with the automaticphotographic gradation-measuring system shown in diagrammatic form;

FIG. 2 is a plan view showing the arrangement of the. lighttransmittorsfor detecting the optical density on the focal lane;

p FIG. 3 is a schematic view of the scanning portion of the system fordetecting the optical density of 'the image represented by thelightquantity transmitted through the light transmittors;-and

FIG. MS a graph showing the output wave pattern of the automaticphotographic gradation-measuring system in accordance with thisinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Now referring to the drawings,the automatic photographic gradation-measuring system will -be describedin anv embodiment employed in a-conventional; photographic printing.apparatus of the automatic exposure value control type. Refer ring toFIG 1, the light from the light source 1 is condensed by the condenserlens 2 to illuminate negative 3. The image of the negative 3 is focusedonto the paper 5 to be printedthrough focusing lens 4. The dispersedlight in the light path between the negativeand the focal plane isreceived by an exposure value-detecting receptor 6 and the receivedlight value is convertedinto the photocurrent. The photocurrent isintroduced into an integrating control device 7 which operates to closethe shutter means 8 when the integrated photocurrent reaches thepredetermined value or the correct exposure is obtained. Thus, .thecorrect exposure is obtained by the conventional photographic printingapparatus. According to necessity, an auxiliary exposure is provided byan auxiliary lamp which has its light quantity controlled to make anoptimum gradation on the paper.

In order to carry out the gradation measurement according to thisinvention, a half silver mirror 10 is provided in the light path and thelight is divided into two focusing parts, one of which is. on the paperand the other of which is on a focal plane for detection 12 by acondenser lens 11. And as describedhereinafter, the negative image istransmitted to the scanning detecting portion 13 and the detectedinformation of density'is amplified by an amplifier l4 and the imagegradation contrast of the negative is measured. The measured value isconverted into a control signal for controlling the auxiliary exposurecontroller 15 to provide a proper exposure with the auxiliary lamp'9.The optical density of the negative image is transmitted through anumber of light transmitters.

The main part of the automatic photographic gradation measuring systemof this invention consists of a number of light transmitters arranged,on the focal plane for detection, to transmit the light from thenegative image to the light receptor and a scanning portion connected tothe amplifier.

The arrangement of the light transmitters is shown in FIG. 2. The end ofthe transmitter is positioned on the focal plane 12 for detection. Thefocal plane 12 is divided into a number of sections ,8 S, S S S,,,,,)and the respective sections are connected to the end of the lighttransmitters.

The scanning portion is shown in FIG. 3, wherein the ends of the lighttransmitters are arranged in a circle and the arranged ends are scannedby another light transmitter 24 connected to a light receptor such as aphotocell 25. The light transmitter 24 is rotated by a motor 23 to scanthe ends of the light transmitters in a circle. By scanning, the lighttransmitter 24 transmits the light to the light receptor 25 and thevarious parts of the focal plane 12 have their optical density detectedand the gradation contrast of the negative image is measured. The lightreceptor 25 provides an electric current of the wave pattern as shown inFIG. 4. The difference between the Fmin and Fmax in FIG. 4 indicates thecontrast of the image. The output current from the light receptor 25 maybe converted into direct current through an amplifier 14 which controlsthe auxiliary exposure controller 15 shown in FIG. 1, and the lightquantity of the auxiliary lamp 9 can be automatically controlled. toprovide an optimum degree of gradation.

Since the gradation contrast of the negative image is provided asan.electric output in accordance with the invention, by providing thedifference between the highest current and the lowest currentrepresenting the highest optical density of ing scanning the image, thegradation contrast of the photographicnegative image can be measuredmuch faster and more. accurately than the conventional measuring methodby the operator himself. Moreover, since the output is in the form of-an..electric,current, the output can be directly utilized tocontrolother exposure controlling means.

The invention has been described in detail with particular reference. toan embodiment thereof, but it will be understood that variations-andmodifications can be effected withinthe scope. of the. invention asdescribed hereinabove and as definedin the appended claims.

Whatis claimedis:

1. An. automatic photographic gradatiommeasuring system comprising: anumber of light-transmitting members, one. end of eachlight-transmittingmember being positioned for detecput corresponding to the gradationcontrast of the negative image from the photocurrent produced by saidlight receptor, and an auxiliary exposure lamp, and means for couplingthe output from said amplifier through an auxiliary exposure controllerto said lamp, whereby the light quantity of the auxiliary lamp isautomatically controlled responsive to gradation contrast.

1. An automatic photographic gradation-measuring system comprising: anumber of light-transmitting members, one end of each light-transmittingmember being positioned for detection at a divided part of a focal planeupon which the negative image is focused, the other end of eachlight-transmitting member being planar arranged in a circular array,another light-transmitting member positioned with a light receptor at anend thereof, the other end of said another light-transmitting memberbeing adapted to scan the ends of said light-transmitting membersarranged in a circular array, an amplifier connected to said lightreceptor to provide an electrical output corresponding to the gradationcontrast of the negative image from the photocurrent produced by saidlight receptor, and an auxiliary exposure lamp, and means for couplingthe output from said amplifier through an auxiliary exposure controllerto said lamp, whereby the light quantity of the auxiliary lamp isautomatically controlled responsive to gradation contrast.